Slash meat on legs in several places. Place legs on plate and cover with barbecue sauce. Marinate 2 hours in refrigerator.
Preheat barbecue at medium-low.
Oil grill and add chicken legs. Cover and cook 20 minutes. If chicken is cooking too fast, open cover slightly. Turn legs once and baste frequently.
Transfer legs to upper grill of barbecue. Cover and continue cooking 25 minutes. Turn legs once and baste frequently. Season to taste.
Serve with grilled yellow summer squash.